Sound Synthesis II: Assignment 2

Assignment 2: Harmonic amplitude extraction

Each of the following sounds contain 7 harmonics based on the pitch of A4 (440 Hz). You must analyze your sound and measure the amplitude of each harmonic present in the sound.

asha.wav

chiajui.wav

eric.wav

ilya.wav

j.wav

After you have measured the amplitude of each harmonic, use the addsyn program on mambo to resynthesize the sound. You can use this example:

   addsyn sound.addsyn output.wav

Verify that your synthesized sound matches the original sound by subtracting the two sounds and seeing if only silence remains:

   subtract yoursound.wav yoursynthesis.wav difference.wav

E-mail me the addsyn script you used to resynthesize the sound when you have finished the assignment.

Extra Credit: what is the secret code encoded into the harmonic amplitudes for your sound?

Hints: The amplitude of the harmonic in a soundfile can be measured with the sndpower program:

   sndpower --all sound.wav

If the sound only contains a sinewave, then the peak amplitude value is the amplitude of the sinewave.

The sms program has an error size of about +/- 0.0001 when identifying the amplitudes. The encoded amplitudes are all increments of 0.001, so you can round the amplitudes up or down to the nearest multiple of 0.001 if you want an exact resynthesis with the addsyn program.